/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.nifi.processors.asana.utils;

import java.util.Iterator;

public abstract class AbstractAsanaObjectFetcher implements AsanaObjectFetcher {

    private Iterator<AsanaObject> pending;

    public AbstractAsanaObjectFetcher() {
        pending = null;
    }

    @Override
    public AsanaObject fetchNext() {
        if (pending == null) {
            pending = fetch();
        }

        if (!pending.hasNext()) {
            pending = null;
            return null;
        }

        return pending.next();
    }

    @Override
    public void clearState() {
        pending = null;
    }

    protected abstract Iterator<AsanaObject> fetch();
}
